Muon transfer from excited states of muonic hydrogen atoms studied by X-ray measurement

Muon transfer from proton to deuteron was examined with muonic X-rays. The parameter q _1s was determined directly and the time spectra of the X-rays were analyzed for effects of the muon transfer reaction. This revised version was published online in August 2006 with corrections to the Cover Date.     

A study of diamagnetic muon bonding in α-quartz using muon spin resonance

Diamagnetic muon spin resonance experiments were carried out in a-quartz at two temperatures: 300 K and 130 K. A strong diamagnetic resonance peak was observed at both temperatures. The spectrum exhibits an anisotropy in the chemical shift of 15 ppm (300K) and 25 ppm (130K).     

Electron microscopy of submicron particles in natural waters—Detection of organic substances

Submicron particles, 0.1–1 m in diameter, in pond water were collected on a 10–20 nm thick carbon film mounted on a carbon coated nylon grid by centrifugation and exposed to osmium(VIII) oxide vapor at room temperature for 2 h. Organic substances reacted with the reagent, while alumino-silicates and hydrated iron(III) oxide as well as the carbon film did not. The X-ray image of osmium revealed that organic substances, presumably humic substances, were associated with most of the particles, especially with hydrated iron (III) oxide, in the pond water.     

Solitons in Polyacetylene Induced and Probed by Positive Mupons

Abstract

Positive muons were injected into both trans- and cis- (CH) as well as (CD)_x. In cis-polyacetylene, the μ⁺ was found to form a radical state with an unpaired electron localized near the μ⁺ In trans-polyacetylene, the longitudinal μ⁺ spin relaxation rate at 293 K showed H^?1/2 dependence on the applied field H. After considering possible mechanisms, we concluded that it is due to the soliton-like one-dimensional motion of induced unpaired electron.     

Study of the trapping of positive muons by extended defects in aluminum

PulsedSR spectra were measured with surface ⁺ in neutron irradiated aluminum as a function of specimen temperature above room temperature. It was found that the depolarization rate of ⁺ increases and the precession frequency decreases as the specimen temperature is raised. This fact was attributed to the trapping of ⁺ by radiation induced voids and suggests the importance of ⁺-surface interactions in the case of voids.     

Time dependent local field felt byμ + in MnO revealed by spin resonance method

By using the muon spin resonance method, the time dependent paramagnetic shift of the ⁺ in MnO was observed at 170 K, where the time-dependence was monitored by changing a timing of rf firing. The advantage of this method is that, compared to the usual transverseSR method, there is no problem associated with a loss of phase-coherence.We acknowledge Prof. T. Yamazaki and Dr. Y.J. Uemura for helpful discussions. This work was supported by the Grant-in-Aid of the Japanese Ministry of Education, Culture and Science.     

μ +SR studies on cis- and transpolyacetylene

Electronic states and depolarization phenomena are studied for the ⁺ in cis- and transpolyacetylene (CH)_x. Formation of weakly bound muonium-like paramagnetic state is found in cis-(CH)_x at room temperature, while diamagnetic ⁺ state is formed in trans-(CH)_x. The origin of this clear difference might reflect properties of excitation modes in these two-isomers.We acknowledge Dr. J.H. Brewer for enthusiastic discussions on the longitudinal decoupling measurements. This work was supported by the Grant-in-Aid of the Japanese Ministry of Education, Culture and Science.     

Observation ofμ − spin precession in ferromagnetic Ni and giant hyperfine anomaly

A ^–SR signal in nickel was found representing the first observation of ^–SR in ferromagnetic materials, and the hyperfine anomaly was determined to be –2.82±0.08% in comparison with the hyperfine field at dilute Co in Ni known from NMR.